In recent years reflecting the use of electronic still cameras and computers, the hard copy technology to record images on paper sheets has been rapidly developed. The goal is to bring the colour reproducibility, image density, gloss and weather resistance of the hard copy to the same level as silver halide photography. Ink jet systems have been used for hard copy recording since full colouring is easy and the printing noise is low. In an ink jet system ink droplets are ejected at high speed from nozzles to a recording material and the ink contains a large amount of solvent which is usually water.
The recording sheet for an inkjet printer is required to swiftly absorb the ink and have good colour forming properties. To reduce the dry time of the ink it has been previously proposed to provide a recording sheet having a porous layer formed on a substrate, the porous layer being formed of an inorganic oxides such as aluminium oxides or silica.
U.S. Pat. No 4,517,244 discloses an ink jet recording material having enhanced fixation rates comprising a support having therein a water insoluble resin having a water absorbing capacity of from 50 to 100 times its own weight.
U.S. Pat. No 5,212,008 discloses a recording sheet which comprises a substrate having two coatings. The first coating comprises (a) a crosslinking agent and (b) a polymer such as a polysaccharide cross linkable by (a). The second coating which is in contact with the first comprises a binder and compound such as an alkoxylated di-fatty quaternary compound.
European Patent Application No 916512 describes a coating fluid for application to a substrate for use in ink jet printing, the coating fluid comprising alumina hydrate particles dispersed in an aqueous medium which contains as binders a polyvinyl alcohol and a polymerisable compound having a hydrocarbon group with a hydroxyl group or a compound having a polyoxyalkylene chain, said compound having a substituent with an unsaturated bond or an epoxy group. The polymerisable compounds disclosed are monomers. The fluid is applied to a substrate such as polyethylene terephthalate, dried and heated with a polymerization initiator to effect polymerization of the polymerizable compound. Compared with the use of polyvinyl alcohol without the polymerizable binder, the advantage stated is that peeling of the coated layer is avoided and good image quality is maintained for a long period of time.